1. Field of the Invention
The present invention relates to parts transfer apparatus for conveying parts or workpieces between adjacent work stations in manufacturing operations.
2. State of the Art
Parts transfer apparatus, such as conveyors, shuttles, etc., are frequently employed in manufacturing operations to convey parts or workpieces between adjacent work stations. Such work stations could be tools, welding presses, stamping presses, etc. Further, one or more idle stations may be provided between each tool or press.
A common parts transfer apparatus is a lift and carry shuttle. Such a lift and carry shuttle includes reciprocating shuttle rails on which various grippers, clamps and locators are mounted for engaging a part or workpiece in one work station and advancing the part or workpiece to the next succeeding work station as the rails are advanced in a forward direction. The rails and the tools or presses are designed such that the rails reciprocally extend through or between such tools or presses. One or more lifter units are connected to the shuttle rails and operate to raise the shuttle rails upward from a lower position to engage a workpiece in a tool or press before the shuttle rail drive is activated to advance the rails in a forward direction to move the workpiece from one tool or press and advance it and all other workpieces on the shuttle rails to the next, adjacent work stations or to an intermediate idle station. At the end of such forward travel, the lifter units retract to lower the shuttle rails to a parts setdown position. The shuttle rails then retract to the start position for the next cycle of operation.
Such lift and carry shuttles include separate drive means, such as motors, fluid operated cylinders, etc., to reciprocate the shuttle rails and to raise and lower the shuttle rails during each cycle of operation. These separate drive units increase the cost of the overall lift and carry shuttle.
Thus, it would be desirable to provide a lift and carry parts transfer apparatus or shuttle having a simplified drive means for a low manufacturing cost. It would also be desirable to provide a lift and carry parts transfer apparatus which can be easily designed for different parts pickup and parts setdown heights.